This invention relates to a sheet material conveying and cutting apparatus of the type shown in prior U.S. Pat. No. 5,189,938 wherein an endless conveyor belt made up of interconnected slat-like support members are used to support and advance sheet material to and from a cutting station, and deals more particularly with improvements in such an apparatus for more readily attaching barrier strips to the interconnected slat-like support members to effect sealing of spacing between juxtaposed slats and the bristle blocks which are attached to them.
In U.S. Pat. No. 5,189,936 issued to Gerber et al., entitled CONVEYOR FOR SUPPORTING AND ADVANCING SHEET MATERIAL AND CUTTING MACHINE INCLUDING SUCH CONVEYOR, a conveyor apparatus is disclosed wherein a conveyor belt comprising a conveying apparatus is made up of interconnected slat-like support members. It has also been found that despite the mechanical engagement which are provided for between the support members as set forth in the aforementioned U.S. Pat. No. 5,189,936, in the form of tongue and groove joints disposed between related slats, that this tongue and groove relationship nevertheless still does not seal the space between two slats, but instead provides a passage through which air is allowed to seep into the bristle bed. These support members each have disposed along one lateral side edge thereof an adhesively attached thin strip of compressible foam plastic material or the like which acts to provide an air seal between adjacent slats to prevent entrance of outside air into the vacuum duct through whatever space that may otherwise exist between adjacent slats. Disposed on the opposite lateral side edge of each support member is an air impermeable barrier strip made, for example, of a thin sheet of gum rubber which extends upwards beyond the slat and along the associated side edge of the bristles of the supporting member and is adhesively secured to the side face of the slat below the bristle block. While such strips have been and continue to be an effective means to effect these stated ends, it has been found, however that during the manufacturing process, that the fabrication of such interconnected slat-like support members is somewhat hindered by the time it takes to fasten such barrier strips to the related sides of each slat. At least with regard to the strip of compressible foam plastic material, this strip usually undergoes successive compression cycles during the course of the operation of the cutter table so as to loose some of its memory capability, and hence its sealing ability. Also, in the past, barrier strips were attached to the slats using an adhesive to bond a portion of the strip to the slat. The process of waiting for setup time in the adhesive and insuring that the edges align with the bottom of the slat to insure that its top edge is correspondingly aligned with the top of the bristles made for additional work which in turn added to the manufacturing time thereby enhancing the cost of slat fabrication. Aditionally, even after assembly, and in the course of normal operation, the reciprocating knife of the cutter makes cuts in the barrier strips to an extent where the strips must be replaced as a matter of regular maintenance.
Accordingly, it is desirable to provide a means by which barrier strips can be readily attached to an associated slot with the relative orientations between the strip and the slat being repeatable form one slat to the next to thereby lower the cost of production of fabrication of the conveyor and insure reliability in product manufacture and further to simplify routine maintenance of the conveyor.
Accordingly, it is an object of the present invention to enhance the seal between related slats in order to improve efficiency in the vacuum holddown capacity of a cutter bed.
Other aspects and improvements offered by the invention will become apparent from the following description and appended claims.